Processes and apparatus for crimping synthetic filamentary materials

ABSTRACT

A process and apparatus for crimping synthetic continuous filament yarn is provided wherein the yarn is drawn in a draw zone to effect orientation of its molecules, and the yarn is thereafter continuously fed from the draw zone to a stuffer box crimper. The drawn yarn is delivered from the draw zone at a temperature elevated by the application in the draw zone of external heat or by the action of drawing to a level to cause interfilament fusion of the yarn within the stuffer box. The drawn yarn is cooled in its passage to the stuffer box to avoid this interfilament fusion.

United States Patent 1 Nicholson et al.

[ 51 Apr. 3, 1973 [75] Inventors: Bruce Nicholson, Rawtenstall; James Mitchell, Egerton, both of England [73] Assignee: T.M.M. (Research) Limited, Lancashire, England [22] Filed: May 10, 1971 [21] Appl. No.: 143,703

Related U.S. Application Data [63] Continuation of Ser. No. 822,273, May 6, 1969,

abandoned.

[52] U.S. Cl ..28/1.6, 28/7214 [51] Int. Cl. ..D02g 1/12 [58] Field of Search ..28/1.6, 71.3, 72.14, 75 WT [56] References Cited UNITED STATES PATENTS 2,311,174 2/1943 Hitt ..28/1.6 2,575,781 11/1951 Barach ..28/72.l4

2,686,339 8/1954 2,807,864 10/1957 2,968,857 l/1961 3,337,930 8/1967 3,373,470 3/1968 3,380,131 4/1968 3,454,998 7/1969 Satterwhite ..28/1.6

Primary Examiner-Louis K. Rimrodt Attorney-Watson, Cole, Grindle & Watson [57] ABSTRACT A process and apparatus for crimping synthetic continuous filament yarn is provided wherein the yarn is drawn in a draw zone to effect orientation of its molecules, and the yarn is thereafter continuously fed from the draw zone to a stuffer box crimper. The drawn yarn is delivered from the draw zone at a temperature elevated by the application in the draw zone of external heat or by the action of drawing to a level to cause interfilament fusion of the yarn within the stuffer box. The drawn yarn is cooled in its passage to the stuffer box to avoid this interfilament fusion.

12 Claims, 2' Drawing Figures PATENTED 3 M 6% 2m yam, 37%46 PROCESSES AND APPARATUS FOR CRIMPING SYNTHETIC FILAMENTARY MATERIALS This is a streamlined continuation application of Ser. No. 822,273, filed May 6, 1969, now abandoned.

The present invention relates to an improved process and apparatus for stuffer box crimping of synthetic continuous filament yarns.

It is known to draw synthetic filament yarns to orientate the molecules and immediately to follow the drawing operation by a stuffer box crimping operation. In order to set the crimp in the yarn whilst in the stuffer box, a certain amount of heat is required. The heat generated in the draw zone, caused either by external heat applied in certain systems, or by the mechanical action of drawing on the filaments, and the additional heat generated by friction between the stuffer box feed rollers and the packed mass of yarn in the box sometimes becomes excessive. This results in interfilament -fusion, and eventually a fusing together of the yarn mass in the lower part of the stuffer box, thereby disrupting the process.

An object of the present invention is to provide an improved process for crimping synthetic filamentary yarns which does not suffer from the above-mentioned drawback and an improved crimping apparatus.

According to one aspect of the present invention, there is provided a process for crimping synthetic continuous filament yarn comprising the steps of drawing the yarn to effect orientation of the molecules, applying an oil or other lubricant to the yarn following the drawing operation and whilst the yarn is at an elevated tem-. perature produced by the drawing action or the application of heat to the yarn, and continuously feeding the lubricated yarn to a stuffer box crimping operation.

According to a second aspect of the present invention there is provided crimping apparatus for crimping synthetic continuous filament yarn and comprising a stuffer box to which drawn filaments are fed from a draw zone in a continuous operation, application means for applying an oil or other lubricant to the 'drawn yarn before crimping thereof in said stuffer box snubbing pins where required.

One embodiment of the invention will now be described by way of example with reference to the accompanying diagrammatic drawing in which FIG. I is a schematic front elevation of crimping apparatus according to the invention; and,

FIG. 2 is a side elevation of part'of the apparatus shown in FIG. 1.

Referring to the drawing, undrawn yarn 1 is taken from a supply package 2 to a pair of rotating rolls 3 and 4 around which the yarn is passed several times. Between these two rolls is situated a heater 5 which imparts heat to the yarn. The yarn is then taken to two further rotating rolls 6 and 7 around which the yarn is again passed several times. The peripheral speed of this second pair of rolls is greater than that of the pair of rolls 3 and 4 and thus the yarn is drawn out to a predetermined degree. A heater 8 may be employed between the second pair of rollers 6 and 7 if required.

From the drawing zone, the yarn 1 is fed into a stuffer box crimper 9 by a pair of feed rollers 10. The feed rollers 10 serve to force the yarn 1 into the crimping chamber 9 and due to its compression against the previously crimped yarn, it is caused to fold back upon itself and thus forms crimped yarn. In order to set the crimp into the yarn, a certain amount of heat is required which, for the reasons hereinbefore discussed, must be kept within acceptable limits.

Situated between the drawing zone and the feed rollers 10 of the stuffer box crimper 9 is a ceramic roller 11 which is arranged to dip into a trough 12 of lubricant. The yarn passes over the roller 11 making substantially tangential contact therewith: the roller 11 rotates in a counterclockwise direction as shown in FIG. 2 so that the yarn at any instant is covered by a substantial amount of the lubricant.

An additional lubricant is supplied to the peripheral faces of the stuffer box crimper feed rollers 10. This ensures that lubricant is conveyed into the base of the stuffer box 9, and particularly to that position where the rollers 10 contact the mass of yarn in the stuffer box 9. Application of the lubricant to the rollers 10 is effected by an oil-saturated felt pad 13 in contact with one of the rollers 10. Alternatively each feed roller 10 may be supplied with lubricant in this manner. The coefficient of friction of dry synthetic yarns on a polished steel surface tends to be high and variable and the use of a suitable lubricant enables a more uniform co-efficient of friction at the point of contact between the rollers l0 and the yarn to be achieved. This is important since the heat generated in the stuffer box 9 is proportional to the co-efficient of friction at this point. By controlling the frictional co-efficient it is possible to keep the heat generated in the stuffer box 9 at a constant level to provide a uniform temperature at which heat setting of the mechanically crimped yarn is accomplished: without friction at a uniform level it is impossible to control temperature in the stuffer box 9.

It has been found that the best crimping results are obtained when the yarn is lubricated by immersion of the roller 11 in the trough l2 and by the application of lubricant tothe feed rollers 10, but for some purposes one or the other means of lubrication may be found sufficient of preferably. In another embodiment of the invention the roller 11 may be provided with a groove through which the yarn may pass.

Where the yarn to be processed is polypropylene a lubricant which is a blend ofvegetable and mineral oils has been found particularly suitable.

What is claimed is:

l. A process for crimping synthetic continuous filarnent yarn comprising the steps of applying the yarn to a draw zone, drawing the yarn in said zone to effect orientation of the molecules, continuously feeding the drawn yarn from the draw zone to a stuffer box crimper, said drawn yarn being delivered from said draw zone at a temperature elevated by the application in the draw zone of external heat or by the action of drawing to a level to cause interfilament fusion of the yarn within the stuffer box, and cooling the drawn yarn in its passage to the stuffer box crimper to a temperature avoiding interfilament fusion of the yarn in the stuffer box by applying a lubricant to the yarn at the elevated temperature induced by the drawing operation.

2. A process according to claim 1 wherein the lubricant is applied by contact of the yarn with a part of the periphery of the rotating roller, another part of the periphery which is immersed in the lubricant.

3. A process according to claim 2 wherein the yarn makes substantially tangential periphery of the roller and the roller is arranged to be rotated against the direction of travel of the yarn.

4. A process according to claim 1 wherein the lubricant is applied to feed rollers employed in the stuffer box crimping operation.

5. A process according to claim 1 wherein the yarn is caused to follow a coiled path in said draw zone immediately before the drawing operation, the yarn being heated in said coiled path.

6. A process apparatus according to claim 5 wherein the lubricant is a blend of mineral and vegetable oils.

7. A process according to claim 5 wherein the lubricant is a blend of mineral and vegetable oils.

8. A crimping apparatus for crimping synthetic continuous the yarn comprising a draw zone, a stuffer box crimper to which drawn yarn is fed in a continuous operation from said draw zone at a temperature elevated by the application in said draw zone of external heat or by the action of drawing to a level to cause contact with the.

interfilament fusion of the yarn within the stuffer box crimper, and application means for applying a lubricant to the drawn yarn at the elevated temperature induced in its passage from said draw zone to the stuffer box crimper to cool the drawn yarn to a temperature at which interfilarnent fusion within he stuffer box crimper is avoided.

9. An apparatus according to claim 8 wherein the application means comprises a lubricating roller, 21 part of the periphery which is immersed in said lubricant, and another part of the periphery over which the yarn passes.

10. An apparatus according to claim 9, wherein the yarn makes substantially tangential contact with the periphery of the roller and the roller is arranged to be rotated against the direction of travel of the yarn.

11. An apparatus according to claim 10, comprising feed rollers for feeding yarn to the stuffer box, and lubricant supply means for supplying lubricant to at least one of said rollers.

12. An apparatus according to claim 11 wherein said draw zone includes first and second rollers between which the yarn is drawn, a third roller arranged to cooperate with one of said first and second rollers for the transport of yarn and to rotate at the same speed as said one of the first and second rollers, and a heater arranged to heat yarn passing between said one of the first and second rollers and the third roller. 

1. A process for crimping synthetic continuous filament yarn comprising the steps of applying the yarn to a draw zone, drawing the yarn in said zone to effect orientation of the molecules, continuously feeding the drawn yarn from the draw zone to a stuffer box crimper, said drawn yarn being delivered from said draw zone at a temperature elevated by the application in the draw zone of external heat or by the action of drawing to a level to cause interfilament fusion of the yarn within the stuffer boX, and cooling the drawn yarn in its passage to the stuffer box crimper to a temperature avoiding interfilament fusion of the yarn in the stuffer box by applying a lubricant to the yarn at the elevated temperature induced by the drawing operation.
 2. A process according to claim 1 wherein the lubricant is applied by contact of the yarn with a part of the periphery of the rotating roller, another part of the periphery which is immersed in the lubricant.
 3. A process according to claim 2 wherein the yarn makes substantially tangential contact with the periphery of the roller and the roller is arranged to be rotated against the direction of travel of the yarn.
 4. A process according to claim 1 wherein the lubricant is applied to feed rollers employed in the stuffer box crimping operation.
 5. A process according to claim 1 wherein the yarn is caused to follow a coiled path in said draw zone immediately before the drawing operation, the yarn being heated in said coiled path.
 6. A process apparatus according to claim 5 wherein the lubricant is a blend of mineral and vegetable oils.
 7. A process according to claim 5 wherein the lubricant is a blend of mineral and vegetable oils.
 8. A crimping apparatus for crimping synthetic continuous the yarn comprising a draw zone, a stuffer box crimper to which drawn yarn is fed in a continuous operation from said draw zone at a temperature elevated by the application in said draw zone of external heat or by the action of drawing to a level to cause interfilament fusion of the yarn within the stuffer box crimper, and application means for applying a lubricant to the drawn yarn at the elevated temperature induced in its passage from said draw zone to the stuffer box crimper to cool the drawn yarn to a temperature at which interfilament fusion within he stuffer box crimper is avoided.
 9. An apparatus according to claim 8 wherein the application means comprises a lubricating roller, a part of the periphery which is immersed in said lubricant, and another part of the periphery over which the yarn passes.
 10. An apparatus according to claim 9, wherein the yarn makes substantially tangential contact with the periphery of the roller and the roller is arranged to be rotated against the direction of travel of the yarn.
 11. An apparatus according to claim 10, comprising feed rollers for feeding yarn to the stuffer box, and lubricant supply means for supplying lubricant to at least one of said rollers.
 12. An apparatus according to claim 11 wherein said draw zone includes first and second rollers between which the yarn is drawn, a third roller arranged to cooperate with one of said first and second rollers for the transport of yarn and to rotate at the same speed as said one of the first and second rollers, and a heater arranged to heat yarn passing between said one of the first and second rollers and the third roller. 